diff options
Diffstat (limited to 'apt-pkg/tagfile.cc')
| -rw-r--r-- | apt-pkg/tagfile.cc | 60 |
1 files changed, 38 insertions, 22 deletions
diff --git a/apt-pkg/tagfile.cc b/apt-pkg/tagfile.cc index 9a7c9734d..68ab7856e 100644 --- a/apt-pkg/tagfile.cc +++ b/apt-pkg/tagfile.cc @@ -1,6 +1,6 @@ // -*- mode: cpp; mode: fold -*- // Description /*{{{*/ -// $Id: tagfile.cc,v 1.16 1998/11/28 03:54:29 jgg Exp $ +// $Id: tagfile.cc,v 1.17 1998/12/07 07:26:22 jgg Exp $ /* ###################################################################### Fast scanner for RFC-822 type header information @@ -115,38 +115,42 @@ bool pkgTagFile::Jump(pkgTagSection &Tag,unsigned long Offset) // TagSection::Scan - Scan for the end of the header information /*{{{*/ // --------------------------------------------------------------------- /* This looks for the first double new line in the data stream. It also - indexes the tags in the section. */ + indexes the tags in the section. This very simple hash function for the + first 3 letters gives very good performance on the debian package files */ bool pkgTagSection::Scan(const char *Start,unsigned long MaxLength) { const char *End = Start + MaxLength; Stop = Section = Start; + memset(AlphaIndexes,0,sizeof(AlphaIndexes)); TagCount = 0; - Indexes[TagCount++] = Stop - Section; - Stop++; - for (; Stop < End; Stop++) + while (TagCount < sizeof(Indexes)/sizeof(Indexes[0])) { - if (Stop[-1] != '\n') - continue; + if (isspace(Stop[0]) == 0) + { + Indexes[TagCount++] = Stop - Section; + unsigned char A = tolower(Stop[0]) - 'a'; + unsigned char B = tolower(Stop[1]) - 'a'; + unsigned char C = tolower(Stop[3]) - 'a'; + AlphaIndexes[((A + C/3)%26) + 26*((B + C/2)%26)] = TagCount; + } - // Skip line feeds - for (; Stop[0] == '\r' && Stop < End; Stop++); + Stop = (const char *)memchr(Stop,'\n',End - Stop); - if (Stop[0] == '\n') + if (Stop == 0) + return false; + for (; Stop[1] == '\r' && Stop < End; Stop++); + + if (Stop[1] == '\n') { - // Extra one at the end to simplify find Indexes[TagCount] = Stop - Section; for (; (Stop[0] == '\n' || Stop[0] == '\r') && Stop < End; Stop++); return true; } - if (isspace(Stop[0]) == 0) - Indexes[TagCount++] = Stop - Section; - - // Just in case. - if (TagCount > sizeof(Indexes)/sizeof(Indexes[0])) - TagCount = sizeof(Indexes)/sizeof(Indexes[0]); - } + Stop++; + } + return false; } /*}}}*/ @@ -157,13 +161,24 @@ bool pkgTagSection::Find(const char *Tag,const char *&Start, const char *&End) { unsigned int Length = strlen(Tag); - for (unsigned int I = 0; I != TagCount; I++) + unsigned char A = tolower(Tag[0]) - 'a'; + unsigned char B = tolower(Tag[1]) - 'a'; + unsigned char C = tolower(Tag[3]) - 'a'; + unsigned int I = AlphaIndexes[((A + C/3)%26) + 26*((B + C/2)%26)]; + if (I == 0) + return false; + I--; + + for (unsigned int Counter = 0; Counter != TagCount; Counter++, + I = (I+1)%TagCount) { - if (strncasecmp(Tag,Section + Indexes[I],Length) != 0) + const char *St; + St = Section + Indexes[I]; + if (strncasecmp(Tag,St,Length) != 0) continue; // Make sure the colon is in the right place - const char *C = Section + Length + Indexes[I]; + const char *C = St + Length; for (; isspace(*C) != 0; C++); if (*C != ':') continue; @@ -173,9 +188,10 @@ bool pkgTagSection::Find(const char *Tag,const char *&Start, End = Section + Indexes[I+1]; for (; (isspace(*Start) != 0 || *Start == ':') && Start < End; Start++); for (; isspace(End[-1]) != 0 && End > Start; End--); - + return true; } + Start = End = 0; return false; } |